The genes for growth hormone (GH), chrionic somatomammotropin (CS) and prolactin (Prl) are a family of structurally related genes which have evolved from a common precursor via gene duplication and are essential for normal mammalian growth and development. The genes are regulated by thyroid and glucocorticoid hormones and represent an important family of genes whose study will aid in understanding hormone action and tissue-specific expression. Our goal is to establish a complete structural and topological analysis of this gene family to provide a foundation for analysis of the expression, hormonal regulation and evolution of this gene family. The genes for human (h) GH and CS form a multigene family which is linked on ca. 100 kb of DNA on chromosome be ordered topologically; the localization and sequence of the interspersed repetitive DNA sequences will be established. The linker regions between hCS and hGH will be sequenced to determine if specific structures related to gene duplication exist. The genomic sequences for hGH and hCS will be extended in the 5 feet and 3 feet direction and their semonal regulation, and tissue-specific expression of these genes. The various hGH and hCS promoters will be compared in cell-free transcription systems to assess the functionality of the genes. Individual hGH and hCS genes will be expressed utilizing SV40 and/or bovine papilloma virus vectors; the products will be tested for binding to growth hormone receptors and biological activity to determine the functional significance of the individual genes; the hormonal regulation of the hGH and hCS genes will be assessed after gene transfer. DNA from human dwarfs and individuals lacking immunoreactive CS will be analyzed by Southern analysis for the presence of deletions or mutations and for linkage to other functions such as growth hormone receptor defects which may yield insinght into gene function. Finally, nuclease sensitivity studies and determinations of methylation patterns for hGH and hCS genes in placenta and pituitary tumors and the binding of nuclear proteins to the hGH and hCS genes will be performed to determine potential factors involved in the tissue specific expression of this gene family.
